1. Field of the Invention
The present invention relates to a method and apparatus for use in a network. The present invention relates particular, but not exclusively, to residential and business broadband internet access provided by service providers.
2. Description of the Related Art
Internet access is typically provided as a relatively simple service, relying on flat rate billing model, i.e., subscribers are allowed to send or receive a limited or unlimited amount of traffic for a fixed monthly fee. In return, subscribers are provided with a best-effort (BE) service, i.e., there are no bandwidth guarantees. Generally, only a maximum access bandwidth is specified in the Service Level Agreement (SLA). This maximum bandwidth is enforced by the Internet Service Providers (ISPs) by applying policy setting at their edge devices handling subscriber sessions, for example Digital Subscriber Line Access Multiplexer (DSLAM) and Broadband Remote Access Server (BRAS).
Transport provisioning of the service providers takes into account the differences in subscriber behaviour like activity, volume of traffic generated etc. That is, it applies an over-subscription to its transport resources. The amount of over-subscription applied is usually expressed in terms of contention ratios. The term contention ratio applies specifically to the number of people connected to an ISP who share a set amount of bandwidth. This may differ depending on the aggregation level of the network where it is applied. Example values would be 50:1, for home users (that is to say that 50 people or lines will vie for the same bandwidth) and 20:1 for business users.
The most common Internet application contributing to excessive usage on the Internet is file-sharing. This is also known as peer-to-peer. These are programs that allow other users on the Internet to access files located on your computer. Some of the more common file-sharing programs are BitTorrent, KaZaa, Gnutella, eDonkey, eMule, fasttracks and Morpheus, some or all of which may be trademarks, registered or otherwise, of their respective owners.
Peer-to-peer traffic now accounts for between 65 and 80 percent of the world's service provider traffic. The traffic is mostly generated by so-called “power-users”, who generally represent a small percentage of the total number of subscribers. Managing the peer-to-peer traffic generated by power users is a significant issue for operators. The available bandwidth per user decreases in case many subscribers uses file-sharing applications. This will manifest in poor overall broadband service and in increased costs due to increased help-desk calls, subscriber turnover, and high peering costs for international traffic. When most of the peer-to-peer content resides outside of their network boundaries, ISPs quickly find themselves losing money when their subscribers download content across international lines.
ISPs have recognized this problem and taken measures for controlling peer-to-peer traffic. This is done by traffic classification and protocol-discovery features that can determine the mix of traffic on the network, which is important in isolating congestion problems.
A known example is a network based application recognition technique, which can identify application/protocols from layer 4 to layer 7 based on packet header information and also deep packet inspection. The applications that network based application recognition can classify include applications that use the following:                Statically assigned (well-known) TCP and UDP port numbers        Non-UDP and non-TCP IP (Internet Protocol) protocols        Dynamically assigned TCP and UCP port numbers during connection establishment. Classification of such applications/protocols requires stateful inspection, that is, the ability to discover the data connections to be classified by parsing the control connections over which the data connection port assignments are made. Identification of the application can, e.g., be based on content signatures of the particular application.        Sub-port classification or classification based on deep inspection—that is classification by looking deeper into the packet. For example classification based on HTTP URLs, mime or host names and RTP Payload Type classification—where network based application recognition looks for the RTP Payload Type field within the RTP header amongst other criteria to identify voice and video bearer traffic.        
Based on the measurements of the traffic classification tools ISPs try to ensure that network bandwidth is used efficiently by policing unwanted connections or setting bandwidth limits for them.
The present applicant has recognised and appreciated the following problems with the existing solutions available.
The above described technologies using traffic classification methods are generally not very efficient. The reason is that the file sharing applications are very flexible: they can adapt to specific situations, e.g., they can hide behind well known protocols or applications like http to cheat the firewall rules. Thus, only a modest percentage of the existing peer-to-peer traffic is recognized by these tools.
Another problem is that the traffic classification tools—especially if they use deep packet inspection—reduce the capacity of the nodes which they are installed on. Since these should be continuously modified due to new appearing applications or mutations of a given application, they cannot be implemented in hardware, so they can usually be run only on software platforms.
Utilizing traffic classification tools also increases the Operations & Maintenance (O&M) efforts considerably. Indeed, a number of O&M tasks should be performed: one has to configure the classification tools, the statistics should be regularly evaluated and the traffic filtering rules should be changed accordingly in the routers. Thus, implementing the above methods represents an increase in operating expenditure for the ISPs.
The operator measures of setting up static rules to filter out or rate limit file sharing traffic is also not very adequate for concurrently satisfying the ISPs goals to reduce customer dissatisfaction during busy hours but at the same time to achieve maximum utilization of the provisioned/rented transport resources. In principle, the filtering and rate limiting measures are needed only in case of traffic congestion; they are unnecessary in the cases of and may lead to low network performance and customer dissatisfaction and ultimately to churn.
It is desirable to address at least some of the above-identified issues.
US 2005/0174944 discloses a scheme whereby the service provider sets a bandwidth usage cap for the subscribers over a given usage period, such as a month. The usage cap is enforced by regulating the rate at which subscribers can send and receive data transmissions over an access network during the usage period. Those subscribers that send or receive data only occasionally will normally experience a transmission rate at or near the peak transmission rate offered by the service provider. However, those subscribers that attempt to send or receive excessive amounts of data will be throttled down to a lower sustained transmission rate, which will prevent them from exceeding the usage cap set by the service provider.
US 2007/0058548 and US 2006/0256718 relate to controlling the traffic entering into a network. The concepts allow setting bandwidth limits for the different flows entering into a network but are not able to dynamically control the volume of traffic based e.g., on current network load situation.
US 2005/0111368 and U.S. Pat. No. 6,910,024 disclose solutions for excessive network usage by providing differentiated pricing. These relate to dynamic charging rather than to traffic limitation. Combinations with a monitoring/traffic regulation system are also proposed in US 2005/0086062 and US 2006/0140369. Different ideas are raised, like royalty charging of copyright material transferred by peer-to-peer applications, etc. These concepts are, however, not applicable to a flat-rate pricing model.